Learning objectives By the end of the subtopic learners should be able to:
Define science and its various departments.
Identify the characteristics of living and non-living things.
Give descriptions of observations.
Label diagrams of observations and laboratory equipment.
Describe and explain laboratory rules.
Science is the study of living and non-living things.
Scientists are people who investigate, observe, discover and record things around them.
There are three departments in Science.
These are Biology, Chemistry and Physics.
Characteristics of living things
They can breathe.
They can feed.
They can grow.
They can move.
They can reproduce.
They can excrete (i.e. pass out waste matter).
They die.
Examples
birds
fish
humans
bacteria
trees
Characteristics of non-living things
They cannot breathe.
They cannot feed.
They cannot grow.
They cannot reproduce.
They cannot excrete.
Examples
stones
soil
wood
glass
air
Use of senses in observation
To be able to observe things you use senses and the brain.
There are five senses which are: hearing, seeing, smelling, tasting and feeling.
Senses enable us to know what is happening around us every time.
Scientists use experiments to find out things. An experiment is a process of finding new things and proving things in a laboratory.
During an experiment we use apparatus. These are tools used during an experiment.
The process of carrying out an experiment is called a method or procedure.
During an experiment you make observations, record and make a conclusion on your findings.
When carrying out an experiment you need to be observant and accurate so that you make correct and accurate recordings.
Apparatus in a laboratory
Laboratory safety rules
There are rules you need to take note of when you are in a laboratory. These include:
1. Do not eat or drink in the laboratory.
2. Do not bring bags and extra books into the laboratory.
3. Do not taste anything unless instructed to do so by your teacher.
4. Do not touch chemicals with bare hands, always put on gloves when working with chemicals.
5. Make sure you understand all instructions and safety measures before carrying out an experiment.
6. Report all accidents to your teacher.
7. Do not run in the laboratory.
8. Handle all laboratory equipment with great care.
9. Put all solid waste into the bin and liquid waste in proper areas provides.
10.Clean apparatus after every experiment and clean all spilled things and broken glass.
Making observations
Experiment: Changes when water is heated.
Apparatus/Materials: beaker, burner, stand, water
Method
Set apparatus as shown above and heat the water.
Look at the water as it is heated in the beaker.
Observations
The water boils, bubbles are seen and steam is produced.
States of matter
Matter exists in three states which are solid, liquid and gas.
Water can exist as ice (solid), liquid and as steam (gas).
When a solid changes to a liquid the process is called melting.
When a liquid changes to a gas the process is called evaporation.
When a gas changes back to a liquid the process is called condensation.
- When a liquid changes to a solid the process is called freezing.
A solid can change to a gas without forming a liquid. This process is called sublimation. Iodine is an example of a substance which changes straight to a gas when heated.
Matter changes states when heat is added or when heat is removed.
Melting occurs when heat is added. Freezing occurs when heat is removed.
Observing different small animals
There are many different small creatures living in different habitats.
These creatures have different behaviours which you can observe.
The small animals above feed on different food, they have different shapes, etc.
You need to be careful when handling some of these animals or insects not to harm or kill them.
After observing make sure you return them to their natural habitat.
Observing colour changes
When doing experiments you also need to observe colour changes.
Solid, liquid and gaseous substances have colour.
There are indicators which show colour changes when mixed with certain substances.
These include:
1. Universal indicator
It is a paper that changes colour in different substances according to their strength in alkalinity or acidity.
2. Bicarbonate indicator
It is a chemical that changes colour in different situations.
It is mostly used to show the concentration of carbon dioxide.
3. Litmus paper
It is a paper that change colour in different substances. It shows alkalinity or acidity.
There is red litmus paper and blue litmus paper as shown below.
The diagram below shows a red litmus paper dipped in an alkaline solution. It changes from red to blue.
When blue litmus paper is dipped in an acidic solution it changes from blue to red.
SUMMARY
Science is the study of living and non-living things.
We use our five senses and the brain to observe in the laboratory. The senses are hearing, tasting, feeling, smelling and seeing.
In the laboratory we use apparatus which include beakers, balances test tubes, Bunsen burners and thermometer.
We are guided by laboratory rules in the laboratory and these should be followed all the time.
